In the field of semiconductor, flat-panel display, or other electronic device processing, as the geometries of electronic devices continue to shrink and the density of devices continue to increase, overall feature size has decreased and aspect ratio has increased. In conventional device fabrication, for example when fabricating a metal gate structure in a two or three dimensional device, to fill smaller features, metal gate material is deposited via a high temperature deposition process atop a wetting layer. Additional layers may be needed, for example one or more barrier layers to prevent diffusion of the metal layer into underlying layers and one or more work function layers to provide a suitable work function for the device. However, the inclusion of the additional layers to perform the aforementioned functions makes it increasingly difficult to create devices having smaller geometries.
Therefore the inventors have provided an improved metal gate structure and methods for forming thereof.